Whenever companies announce the updates on their coronavirus vaccine candidates, they typically mention that some participants experience mild side effects. A report from the journal Science looks into some of the side effects from current clinical trials such as the Pfizer and Moderna vaccines.

Moderna volunteer Luke Hutchinson, a biologist from MIT, experienced swelling on his arm after being administered a second dose. The healthy 43-year-old also experienced boy ache and had a mild fever of 102 degrees Fahrenheit. Even after his symptoms subsided within 12 hours, he said that he wasn't prepared for the severity of side effects.

He believes that the public should. be better informed since some volunteers may experience intense side effects as well, or reactogenicity, from the same clinical trials. Although the vaccine is safe and not cause long-term issues, said vaccinologist Deborah Fuller, how will the public perceive the potential side effects when the Moderna vaccine becomes widely available? If a large number of people report side effects, others may be hesitant to get vaccinated.

Understanding Side Effects

At the same time, both Moderna and Pfizer/BioNTech reported a high efficacy rate in the current clinical trials of thousands of participants around the globe. Both vaccines also use similar technology which is fairly new - adding coronavirus genetic code to a lipid nanoparticle.

Some experts suspect that the immune system reacting to the lipid nanoparticle may be the cause of side effects. Immunologist Claire Bryant from Cambridge University explained that "the side effects when you have the vaccine are a bit like if you had a mild virus infection, not due to the virus infection, but actually due to the way that your body responds."

Less than 2% of participants from both vaccine trials developed severe fevers above 104 degrees Fahrenheit. Other side effects such as fatigue, body pains, and headache were all less than 10%. Epidemiologist Arnold Monto explained that these are higher reactogenicity rates than seen in most flu vaccines. But then again, flu vaccines are only 40% to 60% effective.

Read Also: Volunteer for Pfizer's Experimental COVID-19 Vaccine Shares Side Effects from Trial 

Importance of Transparency

Bernice Hausman from Pennsylvania State University added that company transparency is very important. Naturally, others may share stories of vaccine injury that could be misunderstood or misinterpreted by the public. It's important that companies inform people to expect these side effects and taking medication such as aspirin will help with the pain. Also, the side effects would typically last around one day.

Another important aspect of dealing with volunteers experiencing side effects is having available support such as a hotline or medical centers ready to receive patients. For example, Luke was thinking if he should call 911 or not.

Vaccinologist Florian Krammer also hopes that the side effects won't scare people from getting vaccinated once it's available. After joining Pfizer's trials, he said that side effects such as fever and fatigue may be unpleasant, but are not dangerous. He assures that reactogenicity is a natural part of getting a vaccine and is not a major concern.

Read Also: Pfizer, BioNTech Announce Completion of Phase 3 Study of COVID-19 Vaccine Candidate 

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